Sibilarization and the five irregular plurals
Ten minutes on the topic's two trickier pieces: к/г/х softening to ц/з/с before the plural -и - a towel that becomes пешкири needs nothing extra, but a word ending in х sibilarizes instead of taking any infix - and the five plurals no rule predicts: човек→људи, дете→деца, брат→браћа, око→очи, ухо→уши. Build sentences with both before choosing and translating your way through the rest.
The part of the grammar page this lesson drills — read it here, then use it.
Sibilarization and the fleeting а
When a masculine noun's stem ends in the velar consonants к, г, х, that consonant often softens to ц, з, с before the plural -и - sibilarization: ђак (pupil) → ђаци, бубрег (kidney) → бубрези, орах (walnut) → ораси. For a monosyllabic noun this usually replaces the -ов-/-ев- infix rather than joining it - one-syllable ђак just sibilarizes and adds -и, not *ђакови - but not always: век (century) → векови keeps its к unchanged and takes the infix instead, so a monosyllabic к/г/х-final noun still has to be checked rather than assumed.
Some masculine nouns carry a fleeting а (непостојано а) in their last syllable - a vowel that appears only in the nominative singular to break up an unpronounceable consonant cluster, and disappears once any ending is added: момак (young man) → момци, пас (dog) → пси. Момци shows both changes at once: the fleeting а drops (момак → момц-) and the exposed к sibilarizes to ц before -и.
Irregular plurals to memorize
A handful of very common nouns have a plural that no rule predicts and simply has to be learned as vocabulary: човек (person, man) → људи (people), око (eye) → очи (eyes), ухо (ear) → уши (ears). Очи and уши are relics of the old Slavic dual number, once reserved for naturally paired things.
Дете (child) → деца (children) and брат (brother) → браћа (brothers) are irregular the same way, with a twist: деца and браћа are themselves feminine-singular-shaped collective nouns with special verb agreement, covered in collective-verbal-nouns-b2. For now, just learn the plural word.
| Singular | Plural | What changes |
|---|---|---|
| đak | đaci | k → c |
| bubreg | bubrezi | g → z |
| orah | orasi | h → s |
| momak | momci | nepostojano a ispada + k → c |
| pas | psi | nepostojano a ispada |